Hayley Mills is pretty skilful in this spirited effort from David Swift. She plays posh sister "Sharon" and not so posh sibling "Susan" who meet at one of those summer camps that parents offload their unwanted children to during the long holidays. Needless to say, they cannot stand one another and after causing havoc for just about everyone else, are forced into isolation. It is during this confinement that things start to thaw between them and they realise they are twins - separated at birth when their parents divorced. They concoct a cunning wheeze - the wrong sister will go home to the wron...